This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
A multiple subscriber identity module (SIM) communication device is one that can support simultaneous operation with two or more SIMs. For example, the communication device can have multiple parallel active calls simultaneously, with one call per SIM. One technique to implement this type of operation is to include more than one modem (modulator/demodulator) in the device and connect one SIM to each modem. In this context a modem can be considered to include digital baseband and radio frequency hardware, and modem software running on top of the hardware. However, having multiple independent modems in the device also increases the cost, which can be disadvantageous especially for consumer communication devices (e.g., cellular phones).